|The common thoughts about the cause of damp at ground level – rising damp|
Damp – It is a problem for many houses. Trouble is that we have coined a phrase that clouds our thoughts – ‘Rising’.
Damp is the presence of water in the structure. This water could come from a variety of sources, but we tend to assume that if it is close to ground level that it must be ‘rising damp’. As you can see from the picture above there are a number of routes that ‘rising damp’ can take, however there is a blinding omission.
Lets assume that a wall has had a damp proof course (DPC) installed – this could be physical one (in the form of slates / bitumen / plastic) or an injected chemical one. Most walls these days have such a feature, although there are many reasons against having an injected solution in many solid walls, and we generally assume that they work to a certain extent. So effectively we have a water proof / resistant layer in our walls. Now this layer does not discriminate between water wishing to come up into the structure and that which comes downwards.
This is the missing link in the thought process when it comes to damp. What if it is not ‘Rising Damp’, but instead ‘Falling damp’?
Many walls are covered with cement renders and also suffer from a lack of maintenance by owners leading to cracks and gaps around windows, doors, services etc. These faults lead to water entering into the main wall structure. The water cannot escape to the outside due to the cement render, so it succumbs to gravity and tracks its way down and into the wall. If this is happening around ground floor level (around windows, cills, plumbing etc) then it can easily find its way to the DPC. Then of course the DPC (assuming that it is doing its job) will stop it and the damp will appear just above the DPC in the inner wall. Also worth noting that the plaster on the face of the wall will soak up the water and hence track it below the DPC as well.
So when we get damp meters out it is very easy to diagnose rising damp, when in fact the DPC is working well and the water ingress is from defects in the wall above rather than any other source. So guess what? People are then recommended to have another DPC installed! This of course does not solve the problem.
We really need to get back to first principles, use our brains and diagnose our buildings correctly. Falling damp is very likely in the UK, especially with all the cement renders that have been applied to older solid walls.
If you want a good and intelligent diagnosis on damp then give the Eco Home Centre a call and get a true independent assessment, do not rely on ‘damp specialists’ from damp proofing companies because, guess what, they have products to sell.